Circaea alpina is a facultatively inbreeding complex of six subspecies, each exhibiting different geographic or ecological preferences but with areas of overlap between two or more subspecies in parts of their range. The subspecies form a reticulate pattern of morphologically intergrading populations, some of which are separated only by seemingly minute differences. Other subspecies, were it not for the numerous intermediate plants, appear so dissimilar that some might recognize them as separate species, as has often been done in the past. Five subspecies are in China.